Severe Threat Decreasing Over the Stateline this Evening

Cloud cover for much of Thursday afternoon really brought down the severe threat for northern Illinois and southern Wisconsin.  There were a line of thunderstorms that moved in between 2pm and 5pm, but mainly produced brief heavy downpours.  The thunderstorms were a result of an upper level disturbance that moved in from the southwest.

Skies are mostly dry Thursday evening, with the exception of a few light showers over Rockford, and will likely remain dry until about 9pm or 10pm this evening.  That's when an area of low pressure from the west moves further into Iowa and northwest Illinois.


The low level jet (winds in the atmosphere roughly 5,000ft above the surface) will increase this evening over west-central and northern Illinois.  This will help bring back the chance for widely scattered showers and thunderstorms through Midnight, with any storm activity looking more isolated during the overnight.  Because of the lack of instability and the overall timing of the rain activity the severe threat will stay very low tonight. 

Earlier in the day it appeared that the threat for heavy rain would be possible over the Stateline but that threat has now shifted further north into Wisconsin and northeast Iowa.  This is closer to where the surface low pressure system will travel and where a warm front will be located.  Rainfall totals north of a line from Monroe to Janesville could be in excess of two inches by Friday morning.


Once the cold front passes Friday morning there will be a few wrap-around showers through 8am or 9am before skies clear out by the afternoon.